Interactions

Interactions with Drugs

Based on animal and human studies, valerian may increase the amount of drowsiness caused by some drugs, although this is an area of controversy. Examples include benzodiazepines such as lorazepam (Ativan®) or diazepam (Valium®), barbiturates such as phenobarbital, narcotics such as codeine, some antidepressants, and alcohol. Caution is advised while driving or operating machinery. In one human study, a combination of valerian and the beta-blocker drug propranolol (Inderal®) reduced concentration levels more than valerian alone. A brief episode of confusion was reported in one patient using valerian with loperamide (Imodium®) and St. John's wort (Hypericum perforatumL.).

An episode of agitation, anxiety, and self-injury was reported in a patient after taking valerian with fluoxetine (Prozac®) for a mood disorder (the person was also drinking alcohol). In theory, valerian may interact with anti-seizure medications, although human data is lacking. Valerian tinctures may contain high alcohol content (15-90%) and theoretically may cause vomiting if taken with metronidazole (Flagyl®) or disulfiram (Antabuse®). Valerian may interact with certain drugs metabolized by the liver or vasopressin.

Interactions with Herbs & Dietary Supplements

Based on theoretical concerns, valerian may increase the amount of drowsiness caused by some herbs or supplements.

A brief episode of confusion was reported in one patient during use of valerian with loperamide (Imodium®) and St. John's wort (Hypericum perforatum L.). Nausea, sweating, muscle cramping, weakness, elevated pulse, and high blood pressure were reported after a single dose of a combination product with St. John's wort, kava, and valerian. Valerian may interact with certain herbs and supplements that are metabolized by the liver.

Bibliography

DISCLAIMER:
Natural Standard developed the above evidence-based information based on a thorough systematic review of the available scientific articles. For comprehensive information about alternative and complementary therapies on the professional level, go to www.naturalstandard.com. Selected references are listed below.

Diaper A, Hindmarch I. A double-blind, placebo-controlled investigation of the effects of two doses of a valerian preparation on the sleep, cognitive and psychomotor function of sleep-disturbed older adults. Phytother.Res 2004;18(10):831-836.